From ac3e233d29f7f77f28243af0132057d378d3ea58 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Thu, 6 Dec 2018 11:12:31 -0800 Subject: x86/vdso: Drop implicit common-page-size linker flag GNU linker's -z common-page-size's default value is based on the target architecture. arch/x86/entry/vdso/Makefile sets it to the architecture default, which is implicit and redundant. Drop it. Fixes: 2aae950b21e4 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu") Reported-by: Dmitry Golovin Reported-by: Bill Wendling Suggested-by: Dmitry Golovin Suggested-by: Rui Ueyama Signed-off-by: Nick Desaulniers Signed-off-by: Borislav Petkov Acked-by: Andy Lutomirski Cc: Andi Kleen Cc: Fangrui Song Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20181206191231.192355-1-ndesaulniers@google.com Link: https://bugs.llvm.org/show_bug.cgi?id=38774 Link: https://github.com/ClangBuiltLinux/linux/issues/31 --- arch/x86/entry/vdso/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/entry') diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 141d415a8c80..0624bf2266fd 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -47,7 +47,7 @@ targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so) CPPFLAGS_vdso.lds += -P -C VDSO_LDFLAGS_vdso.lds = -m elf_x86_64 -soname linux-vdso.so.1 --no-undefined \ - -z max-page-size=4096 -z common-page-size=4096 + -z max-page-size=4096 $(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE $(call if_changed,vdso) @@ -98,7 +98,7 @@ CFLAGS_REMOVE_vvar.o = -pg CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds) VDSO_LDFLAGS_vdsox32.lds = -m elf32_x86_64 -soname linux-vdso.so.1 \ - -z max-page-size=4096 -z common-page-size=4096 + -z max-page-size=4096 # x32-rebranded versions vobjx32s-y := $(vobjs-y:.o=-x32.o) -- cgit v1.2.3 From cd01544a268ad8ee5b1dfe42c4393f1095f86879 Mon Sep 17 00:00:00 2001 From: Alistair Strachan Date: Fri, 14 Dec 2018 14:36:37 -0800 Subject: x86/vdso: Pass --eh-frame-hdr to the linker Commit 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link") accidentally broke unwinding from userspace, because ld would strip the .eh_frame sections when linking. Originally, the compiler would implicitly add --eh-frame-hdr when invoking the linker, but when this Makefile was converted from invoking ld via the compiler, to invoking it directly (like vmlinux does), the flag was missed. (The EH_FRAME section is important for the VDSO shared libraries, but not for vmlinux.) Fix the problem by explicitly specifying --eh-frame-hdr, which restores parity with the old method. See relevant bug reports for additional info: https://bugzilla.kernel.org/show_bug.cgi?id=201741 https://bugzilla.redhat.com/show_bug.cgi?id=1659295 Fixes: 379d98ddf413 ("x86: vdso: Use $LD instead of $CC to link") Reported-by: Florian Weimer Reported-by: Carlos O'Donell Reported-by: "H. J. Lu" Signed-off-by: Alistair Strachan Signed-off-by: Borislav Petkov Tested-by: Laura Abbott Cc: Andy Lutomirski Cc: Carlos O'Donell Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Joel Fernandes Cc: kernel-team@android.com Cc: Laura Abbott Cc: stable Cc: Thomas Gleixner Cc: X86 ML Link: https://lkml.kernel.org/r/20181214223637.35954-1-astrachan@google.com --- arch/x86/entry/vdso/Makefile | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86/entry') diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 0624bf2266fd..5bfe2243a08f 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -171,7 +171,8 @@ quiet_cmd_vdso = VDSO $@ sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \ - $(call ld-option, --build-id) -Bsymbolic + $(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \ + -Bsymbolic GCOV_PROFILE := n # -- cgit v1.2.3